Blaster Knuckle is a manga series by Shizuya Wazarai, serialized in Young Animal during 1992.
Take yourself back to the 1880s where the KKK is thriving and the African American community lives in fear. The African Americans don't fear the KKK simply because they beat, rape, and kill them. No. They fear the KKK because the KKK eats them. They are the aptly named man-eaters, a kind of mix between werewolves and vampires. They consume human flesh, can shapeshift into various forms, and are practically immortal. Only one man, an ex-heavyweight boxer named Victor Freeman, dares to stand up to them. Equipped with a small arsenal and a set of modified brass knuckles, can our hero defend his people and avenge his past?